This invention relates to drive circuitry and drive methods for plasma display panels of the alternating current type capacitively coupled to an ionizable gaseous medium. In particular, this invention relates to the clamp circuits which are used in selecting drive lines to be driven in various operations of a plasma display panel. In particular, self-actuating clamps are shown for both polarities of applied voltage which are self-actuating during the normally ON sustain drive mode of the plasma display panel. There is substantial prior art relating solely to drive circuits for plasma display panels. All of these patents represent efforts at improving the cost and efficiency factors of plasma display circuit design. Improvement has been through use of low voltage rather than high voltage switching devices as well as use of drive techniques which requires a minimum number of electronic devices for the overall drive system.